The existing electromagnetic relay usually includes a contact block, a magnetic system and a pushing block. The contact block includes a normally-closed fixed contact piece assembly, a normally-open fixed contact piece assembly and a movable contact piece assembly. These assemblies are disposed into the base in cartridge inserted way, forming a stable and reliable contact block. The magnetic system includes a yoke, an armature, a bobbin and a coil winding. The contact block and the magnetic system are assembled into the base to integrate into a relay. In the above structure of relay, the motion of the armature is passed to the movable contact piece through the pushing block. One end of the pushing block is assembled in stuck way to form pin joint with the armature head. The armature and the pushing block can rotate relatively in a certain angle range with the pin joint, which is served as the axis. The other end of the pushing block disposed with a bump is shoved into the notch of the movable contact piece in lap joint way. When the coil of the relay isn't energized, the normally-closed fixed contact set retains connected, the pushing block and the movable contact piece is in free lap joint. When the coil of the relay is energized, the armature moves toward the yoke, the pin joint portion drives the pushing block move, the pushing block pass the motion of the armature to the movable contact piece, the movable contact piece moves to cut off the normally-closed fixed contact set and connect the open static contact. With the electromagnetic force of the powered coil, it maintains that the closed static contact is cut off and the normally-open fixed contact set is connected.
FIG. 1 illustrates the integrated structure of the existing relay; FIG. 2 illustrates the breakdown structure of the existing relay; FIG. 3 illustrates the assembly structure of the armature and the pushing block of the existing relay; FIG. 4 illustrates the assembly process of the armature and the pushing block of the existing relay.
The structure of the relay includes a base 1′, a pushing block 2′, an armature3′, a yoke 4′, a bobbin 5′, a coil 6′, a normally-closed contact set 7′, a normally-open contact set 8′ and a movable contact piece 9′; a bump 31′ and a convex bract 32′ are disposed on the head of the armature 3′; a hole 21′ and a concave stage 22′ are disposed in one end of the pushing block 2′; the thickness of the bump 31′ on the head of the armature 3′ is less than the width of the hole 21′ of the pushing block. However, the thickness of the concave bract 32′ on the head of the yoke 3′ is more than the width of the hole 21′ of the pushing block. When the armature 3′ and the pushing block 2′ are assembled, the bump 31′ on the head of the armature 3′ is shoved into the hole 21′ of the pushing block with the convex bract 32′ is interferencefit assembled.
After assembly, the concave stage 22′ of the pushing block is served to limit the convex bract 32′ of the armature head. Without external force, the armature 3′ can not be divorced away from the hole 21′ of the pushing block. As the thickness of the bump 31′ of the armature head is less than the width of the hole 21′ of the pushing block, the armature 3′ can rotate in an certain angle range. This is the pin joint of the armature 3′ and the pushing block 2′. When the armature 3′ moves forwards or backwards, the yoke 3′ drives the pushing block move forwards or backwards. Then the pushing block 2′ drives the movable contact piece move for contact switch.
However, in the assembly process of the structure of the relay, as the assembly of the armature 3′ and the pushing block 2′ is interferencefit, the assembly is building with plastic waste, which will cause the contact unusable and the dysfunction of the relay. Besides, the interferencefit construre makes the pushing block 2′ disassembled with damaged when the armature 3′ is assembled to the pushing block 2′.